A blasting apparatus may typically comprise an array of detonators and associated explosive charges, connected via wire signal transmission lines (e.g. branch lines and trunk lines) to one or more associated blasting machines. The detonators may receive a command signal to FIRE through the signal transmission lines. In the case of electronic detonators, the command signals may further include more complex instructions including, but not limited to, signals to ARM, DISARM, ACTIVATE, DEACTIVE, or SHUTDOWN the detonator, or may include firing codes or delay times.
Often, detonators are positioned at a blast site in operative association with a booster. Typically, a booster may comprise a discrete portion of explosive material retained or partially retained within a cup-like member or within a suitable recess. During use at a blast site, a detonator, or more particularly a percussion-actuation end of a detonator comprising a small base charge, may be positioned adjacent the explosive material in the booster. Successful receipt by the detonator of a command signal to FIRE may result in the initiation of the detonator's base charge, which in turn causes actuation of the explosive material of the booster. If required, the booster may be in operable association with further explosive material such as a cross-linkable explosive emulsion, for example positioned down a borehole in rock, such that actuation of the booster in turn causes actuation of the further explosive material, causing more powerful shockwaves for rock fragmentation.
The integrity of the connections between the detonators and an associated blasting machine is paramount. Poor connections may result in detonator failure during a blasting event, for example due to improper transmission and receipt of command signals by the detonators. Detonators that fail to actuate in response to a command signal to FIRE present a significant safety concern at the blast site. Retrieval of such failed detonators, and their associated explosive charges, may present a hazardous process.
Proper establishment of a blasting apparatus at a blast site requires positioning of detonators and associated boosters at desired positions in the rock, and “tieing-in” of the detonators to at least one corresponding blasting machine. This “tieing-in” process is labour intensive and required considerable skill and diligence of the blast operator. The blast operator must ensure that detonators are properly associated with boosters at each position in the rock, lay trailing wires from each detonator to a corresponding blasting machine, and ensure that the electrical connections between each detonator and each trailing wire, as well as each trailing wire and each blasting machine, are properly established.
In other blasting apparatuses known in the art, detonators are manufactured and shipped with trailing wires already secured therein. Whilst this avoids the need to “tie-in” the detonators to the trailing wires at the blast site, shipment and usage of such preassembled detonator/trailing wire combinations can be problematic. Numerous wire strength/length combinations must be manufactured and available for the consumer, resulting in higher manufacturing costs. Moreover, due to the presence of small quantities of explosive material, detonators must be shipped and handled carefully in accordance with strict regulations. Preassembly and shipment of detonators with attached trailing wires can significantly increase the cost and logistics of the shipment process.
There remains a continuing need to develop blasting apparatuses, and components thereof, which permit rapid and reliable establishment of the blasting apparatus at the blast site. In particular, there is a need for blasting apparatus components that enable hazardous components of the blasting apparatus to be separately shipped to a blast site, and assembled with non-hazardous components quickly and easily. In particular, there is a need for a blasting apparatus in which booster components and detonator components may be separately shipped to a blast site, and assembled without significant difficulty into a robust and reliable booster assembly.